Why is everything just a fight?

And I mean everything. Literally everything.

Eating. Drinking. Getting dressed. Brushing teeth and hair. Bath time.

To bed time. To quiet/nap time. To literally just laying down. To just literally existing.

Every single thing. Every single day.

Why does every single day feel like I am just at war with this tiny human for every single thing that they do? And why do I always feel like the most terrible parent for getting frustrated and setting boundaries?